Insecticide poisoning is exposure to a group of chemicals designed to eradicate insects that cause affected persons to develop clinical signs that can progress to death.
Insecticides belong to a group of chemicals called organophosphates used to protect against insects. Their use is popular since they are effective and do not remain in the environment, disintegrating within a few days. Organophosphates act to inhibit an enzyme in humans called acetyl cholinesterase. This enzyme functions to degrade a chemical called acetylcholine, which excites nerve cells. The resultant effect of organophosphates would be an increase in acetylcholine, thus causing initial excitation of nerve cells. Insecticide poisoning is often called carbamate poisoning and pesticide poisoning as well.
Poisoning can occur with a broad range of symptoms affecting the functioning of nerves and initial symptoms similar to the flu such as vomiting, abdominal pain, dizziness, and headache. Common names for insecticides are dichlorvos, chlorpyrifos, diazinon, fenthion, malathion, parathion, and carbamate. A special type of insecticide called paraquat is lethal and responsible for approximately 1,000 deaths per year in Japan alone. Paraquat poisoning releases oxygen free radicals that destroy lung and kidney tissues. When poisoning is suspected, a comprehensive management and assessment plan should be performed. This initial assessment should include:
As of 2012, the Environmental Protection Agency estimated that 10,000–20,000 physician-diagnosed pesticide poisonings occurred each year among the approximately 2 million U.S. agricultural workers. Agricultural workers, groundskeepers, pet groomers, fumigators, and workers in a variety of other occupations are at risk for exposure to pesticides, including fungicides, herbicides, insecticides, rodenticides, and sanitizers.
Exposure to insecticides can occur by ingestion, inhalation, or exposure to skin or eyes. The chemicals are absorbed through the skin, lungs, and gastrointestinal tract and then widely distributed in tissues. Symptoms cover a broad spectrum and affect several organ systems:
Individuals should decontaminate exposed clothing and wash with soap and water immediately. Emergency measures may focus on ventilator support and heart monitoring. If inhalation is suspected, the patient should be removed from the site of exposure. If the eyes were the entry site, they should be flushed with large amounts of water. If the chemicals were ingested, the stomach may be washed out and activated charcoal may be administered. Atropine or glycopyrrolate (Robinul) is the drug of choice for carbamate insecticide poisoning. It reverses many symptoms but is only partially effective for central nervous symptom effects such as coma and convulsions. Pralidoxime is also commonly indicated to reactivate acetylcholinesterase and to reverse typical symptoms due to organophosphate poisoning. Additionally, the patient is monitored for heart, lung, liver functioning; specific blood tests; and oxygen levels in blood.
Prognosis depends on the specific chemical of exposure, magnitude and time of exposure, progression of symptoms (severity), and onset for medical attention.
Adherence to accepted guidelines for handling and management is the key to preventing insecticide poisoning. These may include using masks, gowns, gloves, goggles, respiratory breathing machines, or hazardous material suits.
The National Institute for Occupational Safety and Health (NIOSH) established the Sentinel Event Notification System for Occupational Risks-Pesticides Program (SENSOR-Pesticides) in 1987 to reduce the number of injuries and illnesses associated with occupational pesticide exposure.
The program is a U.S. state-based surveillance effort that monitors pesticide-related illness and injury in 11 states. Under this program, NIOSH provides technical support and funding to state health departments to build and maintain surveillance capacity and to bolster pesticide-related illness and injury surveillance. The U.S. Environmental Protection Agency (EPA) also provides funding for the program.
The SENSOR-supported surveillance systems tabulate the number of acute occupational pesticide poisonings, allowing for the timely identification of outbreaks. The program also helps develop preventive interventions and maintains a national database that compiles information from participating states. Researchers and government officials from the SENSOR-Pesticides Program publish articles highlighting findings from the data and build state and national capacity by facilitating communication across participating states. Publications discuss issues as diverse as pesticide poisoning among agricultural workers, pesticide poisoning in schools, birth defects, and residential use of total release foggers (bug bombs, devices that release an insecticide mist).
See also Environmental Protection Agency (EPA) ; National Institute for Occupational Safety and Health .
Borron, S. W. “Pyrethins, Repellants, and Other Pesticides.” In Haddad and Winchester's Clinical Management of Poisoning and Drug Overdose. 4th ed. Edited by M. W. Shannon, S. W. Borron, M. J. Burns, chap. 77. Philadelphia: Saunders Elsevier, 2007.
Goldman, Lee, and Andrew I. Schafer, eds. Cecil Medicine. 24th ed. Philadelphia: Saunders, 2011.
Laith Farid Gulli, MD